Specifications - Lord and Son Construction, Inc.

j. Filter boxes.
k. Mixing boxes (field-insulated).
l. Supply fans (field-insulated).
m. Site-erected air conditioner casings.
n. Ducts exposed to weather.
o. Combustion air intake ducts.
Insulation for rectangular ducts shall be flexible type where concealed,
minimum density 3/4 pcf, and rigid type where exposed, minimum density 3
pcf. Insulation for both concealed or exposed round/oval ducts shall be
flexible type, minimum density 3/4 pcf or a semi rigid board, minimum
density 3 pcf, formed or fabricated to a tight fit, edges beveled and joints
tightly butted and staggered. Insulation for all exposed ducts shall be
provided with either a white, paint-able, factory-applied Type I jacket or a
field applied vapor retarder/vapor barrier jacket coating finish as
specified, the total field applied dry film thickness shall be approximately
1/16 inch. Insulation on all concealed duct shall be provided with a
factory-applied Type I or II vapor retarder/vapor barrier jacket. Duct
insulation shall be continuous through sleeves and prepared openings except
firewall penetrations. Duct insulation terminating at fire dampers, shall
be continuous over the damper collar and retaining angle of fire dampers,
which are exposed to unconditioned air and which may be prone to condensate
formation. Duct insulation and vapor retarder/vapor barrier shall cover the
collar, neck, and any un-insulated surfaces of diffusers, registers and
grills. Vapor retarder/vapor barrier materials shall be applied to form a
complete unbroken vapor seal over the insulation. Sheet Metal Duct shall be
sealed in accordance with Section 23 00 00 AIR SUPPLY, DISTRIBUTION,
VENTILATION, AND EXHAUST SYSTEM.
3.3.2.1 Installation on Concealed Duct
a. For rectangular, oval or round ducts, flexible insulation shall be
attached by applying adhesive around the entire perimeter of the duct
in 6 inch wide strips on 12 inch centers.
b. For rectangular and oval ducts, 24 inches and larger insulation
shall be additionally secured to bottom of ducts by the use of
mechanical fasteners. Fasteners shall be spaced on 16 inch centers and
not more than 16 inches from duct corners.
c. For rectangular, oval and round ducts, mechanical fasteners shall
be provided on sides of duct risers for all duct sizes. Fasteners
shall be spaced on 16 inch centers and not more than 16 inches from
duct corners.
d. Insulation shall be impaled on the mechanical fasteners (self stick
pins) where used and shall be pressed thoroughly into the adhesive.
Care shall be taken to ensure vapor retarder/vapor barrier jacket
joints overlap 2 inches. The insulation shall not be compressed to a
thickness less than that specified. Insulation shall be carried over
standing seams and trapeze-type duct hangers.
Section 23 07 00 Page 26